Thanks for answering!

You answer was really helpful, thanks a lot! It helped me visualize the problem. I think I found a way to solve it but I'm not quite sure. I try to follow your solution but I don't know how you build the x^4 equation.

Anyway, I came out with a solution. I'm not so sure about it but I'm posting it if anybody can tell me it's a good or bad reasoning.

Double integral of a function on a region delimited by quadratic functions

Well about building equation. It's simple! If we want to find the coordinates of "point" we should put these two equations equal to each other. and then we get . I can solve this equation with maple, but I would like to solve it in a classic way! The answers are x=1.767469062 and x=2.263652586. But we only need the first one. I used x=1.77 for simplicity. Then y=0.87.

My answer is "33.83" which is equal to yours, but I solved it on my own at first and then checked it with maple!